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Infants born prematurely are known to display longstanding bronchial hyperreactivity. The mechanism responsible for this is still unclear. Eosinophils are thought to play a central part in the development of bronchial hyperreactivity in asthma. It was the aim of this study to assess the relation of bronchial hyperresponsiveness to potential markers of eosinophilic inflammation in peripheral blood. Eosinophil count, the concentration of serum eosinophilic cationic protein, the capacity of purified eosinophils to generate leukotriene C4, and bronchial reactivity was studied in 24 non-atopic children born prematurely, 12 healthy controls, and 12 children with asthma aged 6 to 9 years. There was no difference in serum concentrations on eosinophil cationic protein and eosinophil counts. However, eosinophils from the 15 formerly preterm infants with significant bronchial hyperreactivity generated significantly higher amounts of leukotriene C4 than normal controls and prematurely born children without bronchial hyperreactivity. Levels of leukotriene C4 in this group were comparable with those obtained with eosinophils from patients with asthma. In contrast with cells from the other groups, eosinophils from the children with bronchial hyperreactivity born prematurely show no enhancement of leukotriene C4 generation on prestimulation with platelet activating factor. It is concluded that bronchial hyperreactivity of children born prematurely is accompanied by the prestimulation of eosinophils. [ABSTRACT FROM AUTHOR]

To assess the relation among eosinophil-related variables in the peripheral blood, bronchial hyperreactivity, and the presence of atopic dermatitis in children aged 5-14 years, we studied 11 patients with atopic dermatitis alone, six with asthma and atopic dermatitis, 12 with asthma alone, and 12 healthy controls. Eosinophil counts, levels of eosinophil cationic protein, and the capacity of eosinophils to generate leukotriene (LT) C4, as well as bronchial hyperreactivity and a severity score for atopic dermatitis, were determined. Eosinophil variables were significantly higher in both patient groups with atopic dermatitis than in normal controls. In particular, ionophore A 23187 LTC4 generation was higher in patients with atopic dermatitis alone (median 82, range 25-273 ng/106 cells) and patients with combined asthma and atopic dermatitis (median 68, range 32-583 ng/106 cells) than in normal controls (median 9, range 1-67 ng/106 cells). However, there was no difference between the group of atopic dermatitis patients with asthma and without asthma. We conclude that eosinophil variables in the peripheral blood are mainly influenced by the presence of atopic dermatitis, and not the presence and the severity of asthma in patients with both asthma and atopic dermatitis. [ABSTRACT FROM AUTHOR]